This invention relates to an improvement in ski boots, particularly in regard to the manner in which the ski boot functions with respect to the foot and the leg of the skier in turning or maneuvering.
In skiing, the skier turns by shifting his weight so that it is temporarily transferred to either the inside or the outside edges of his skis. This causes an unbalanced effect on the skis, and they turn in the direction of the weighted edges. In short, it is this weighting and corresponding unweighting of the sides of the skis which permits the skier to maneuver as he skis down a hill.
In the prior art, the ski boot is locked to the ski by the binding and the ski boot cannot move in any direction without producing a corresponding movement in the ski. As the foot and the ankle of the skier are firmly and substantially immovably held in the prior art ski boot so that movement of the skier's foot without moving his leg is not possible, the skier turns by twisting his entire torso. The knees of the skier are laterally moved in the direction of the turn, bending his lower legs outwardly causing the boot to tilt and thereby shifting weight to the edge of the ski as required. Unfortunately, this lateral movement of the knee tends to turn the foot itself and the ski in the opposite direction against the turn. As a result, the skier expends a substantial amount of energy in turning and experiences a substantial strain particularly with respect to the knees.
Furthermore, as a result of this arrangement the prior art ski boots must be fabricated so that the sidewalls are strong enough to lock the ankle and foot in place, but at the same time flexible enough to permit the skier to bend his leg laterally in order to turn.
The prior art ski boots, therefore, do not take advantage of the foot's natural lateral tilting movement, which is known as inversion and eversion. In terms of bone structure, the foot has a subtalar joint, formed by the talus and the oscalis, which is responsible for most of the lateral movement of the foot. Because of this subtalar joint, the foot can be tilted without moving the remainder of the leg, and it is, therefore, possible to shift the weight of the body just by inverting or everting the foot without laterally moving the knees or twisting the torso. However, the subtalar motion or inversion and eversion of the foot cannot exist if the ankle and the foot are held in place as they are in prior art ski boots some of which are even form fitted to the individual's feet.
Accordingly, the prior art ski boot design is unsatisfactory from a number of standpoints, particularly since it does not permit the skier to turn easily without a great expenditure of energy and stress on various parts of the body, such as the knees and torso.